US1999950A - Liquid and gas separator - Google Patents

Description

April 30, 1935. ,M. F. WATERS LIQUID AND GAS SEPARATOR Filed July 11, 1933- sheets-sheet 1 Gttomeg S v M. F. WATERS LIQUID AND GAS SEPARATOR April 30,1935.

Filed July 11, 1935 2 Sheets-Sheet 2 attorney 5 Patented Apr. 30, 1935 PATENT OFFICE LIQUID AND ens ssrm'roa Millard F.v Waters, Tulsa, 0th., assignor to Hanlon-Waters, 1nc., Tulsa, Okla.

Application July 11, 1933, Serial No. 679,963

14 Claims.

My invention consists in new and useful improvements in liquid and gas separators primarily adapted for separating oil and gas, and relates more particularly to improvements on the general principle of structure and operation of the device shown and described in my former Patent No. 1,910,728, issued May 23, 1933. As in the case of my former invention; it is my main object to provide a structure for taking advantage of the principle of differences in the mass or density in the liquids or solids and gases through expansion of the gas which is the carrying agent of the liquid or solid, and including a series of collecting surfaces in direct line with the flow of the mixture.

In other words, the basic principle of the invention resides in the utilization of the effect of the velocity of the fluid to separate and maintain separation of the liquids and gases.

Heretofore in oil and gas separators ithas been diflicult to prevent the oil from spraying over into crease in velocity of the gas through the separating unit or where the gas leaves the separator, the liquid was mechanically carried over. Also due to the construction of most separating units,

the pressure at the top of the down-comer pipes at certain times being less than that at the bot,- tom of the tank, would permit the liquid to immediately enter and rise in the down-comer pipes, coming in contact with the high velocity gas and being carried out therewith.

It is the object of my present invention to eliminate this disadvantage which I accomplish by the application of two principles. First, in place of the separating unit heretofore employed in oil and gas separator tanks including my own former unitfI install a cylindrical unit with a cylindrical chamber in the center thereof which is so designed as to contain at all times more gas at a given pressure than can be taken out of the gas outlet at the top of the tank at the same pressure, thus eliminating a pressure drop through the unit and permitting gas to be fed into said chamber in greater volume than can be discharged therefrom by the gas line at the top of the tank at the same pressure. This prevents an increase in the velocity of the gas regardless of the fluetuation of the pressure in the gas line leading from the separator. Second, I employ a vertical check valve in the liquid down-comer pipe leading from the separator unit to the lower portion of the tank by means of which, if there is a tendency of the oil in the tankto bubble or boil due to the lighter fractions of oil being taken out of the gas or due to the difference in temperature of the oil in the bottom of the-tank, which would cause the oil to start back up the down-comer pipe, the backing up of said oil is'immediately prevented until such time as the pressure on the inside of the separator is equalized or the weight of the accumulated liquid on the top side of the valve is suflicient to overcome any difierence in pressure, whereupon the valve opens to permit the downflow of oil from the separating unit.

A further object of my invention resides in my improved oil outlet by means of which disturbance in the liquid level is prevented by eliminating the possibility of a rush of oil toward the outlet.

A still further object of my invention resides in the design of separating unit which can be constructed so as to equip any conventional tank with as many square feet of surface contact as may be desired, increasing or decreasing the efliciency of the separator by the relative number of square feet of surface contact in the separating unit. With my design, I can provide amaximum of surface contact which together with the principle of expansion are the fundamental factors of liquid and gas separation.

Another object of my invention is to provide means for preventing the liquid in the bottom of the tank from being mechanically picked up due to the velocity of the gas whirling around the inside of the shell.

With the above and other objects in view which will appear as'the description proceeds, my invention consists in the novel features herein set forth, illustrated in the accompanying drawings and more particularly pointed out in the appended claims.

Referring to the drawings in which numerals of like character designate similar parts throughout the several views,

Fig. 1 is a perspective view of my improved oil and gas separator equipment with a portion of the tank wall broken away to illustrate the structure of the separating unit or mist extractor per se, the latter also being shown partly in section.

Fig. 2 is a transverse sectional view taken on line 2-2 of Fig. 1.

Fig. 3 is a sectional view through a portion of the tank showing the conical baflle for preventing the liquid in the tank from being mechanically picked up, and V Fig. 4 is a partially disassembled ,viewgof the separating unit showing the structure of the various component parts thereof.

Inthe drawings, a conventional oil-and gas separator tank having-one or more inlet flanges 2 throughwhichia mixture of-oil and gas from the wellorwelis is introduced into means-and comprises a flatv plate .which extends mediately .back of the inlet the baiiie has the j 25 across the the inlet flange, said platebeing directed at a slight downward angle as shown in dotted lines in Fig. 1 and flaring towards its discharge .end I, its opposite end-closely engaging the inner wall of The upper and lower extremities of the plate are bent at rightangles toward the shell of the tank to form flanges orwings I, the: edges of which are correspond with the-contour of said terbywelding.'

These inlet baiiies are so constructed that imcapacity of the-inlet flange and then begins to flare principally "at a' downward angle toward the discharge end of the baiiie, the space between the discharge end of flat plate 6 and the shell of the separator being approximately one inch, but the baiiie having-such vertical-dimensionsnas to have the capacity of the inlet. The vertical-opening I in the end of the baiiie is restricted, and

due to its flare and angle of discharge, oil and gas entering the tank are spread out in a thin fllm and directed in a circumferential path around the shell of the separator as will hereinafter appear. It will be noted that in order to provide for an expansion of the of oil and gas as. it enters the separator, the combined areas of the v oil and gas outlets leading from the separator are greater than the combined areas of the inlets leading into the separator.

In the upper portion of the-tank I, 'I provide a mist extractor or separating unit I which is substantially cylindrical in shape and comprises a plurality of vertically a; separating elements or baiiies ll arranged in a series of coaxial circular rows in staggered relation as clearly shown in Fig. 3. The individual separating elements ll are constructed essentiallyin. the same manner as those shown and described in my former Patent'No. i,9l0,728 hereinbefore referred to, and consist of elongated tube-like structures substantially semi-circular in cross section at their rear extremities, their side walls being straight and flaring slightly outwardly toward their forward extremities. The vertical forward edges of the sidewalls are bent inwardly toward one another at an angle of substantially 45 to form inw'ardlydirected flanges, the free edges of which are spaced apart to leave a vertical opening within and substantially centrally of the forward extremity of each member l0. Thus when these baiiies or separating elements are arranged, as before mentioned, in co-axial circular rows in staggered relation, spaces or passageways are provided between each baiiie,-which passageways gradually expand toward the axis of the separating unit, each passageway being in direct line with the vertical opening of the respective baiile of the row next behind.

Due to the'fact that the diameter of the rows of baflies decrease toward the axis of the separating unit-and in order to provide-an emcient assembly following out the principle of operall thelat zseparation "but-thegbottom-i tion embodied herein, it is desirable to correspondingly; decrease the size 'of the individual' next two. rows of baniesbeing made up of vertlcallydisposed angle-irons or the like lfla, the flrst row'of angles with which the gas contacts,

. being preferably of 80' and the next row It, pref erably .909.

members'yll fsuitablyfrduced in size, but from a --It wi il.be"understoodthat therows of Ms I all and'llcmay becomposed of members cons r ctedin .accorda nce-withthe shape of the a practical and ecohomicalstandpoint, I have found -mtjthegangleiirons ifare entirely satisfactory to 3 a y "th 'desiredfunction at stage of the owever .Iidosnot wish to-iim'it my-'- .elementsiin'i 'is'. 4. I

ess verticalbafliesrare retained swamps. 1 v relative by means of circular plates or discs- II .a'n'd' fll, saidplates being punched to of separating I accommodatethefends of the baflies. The top plate liiis provided with a, central opening 18' v .qcr-platejis solid with the ex-- v ceptioiiI-ot {the provided ".ror 'the accommodatiQn ofthe names. 1 The upper ends of the bames are 'flushywithxthe top surface of the spacer platel! while their. lower ends extend through thefbottom spacer plate n m a predetermined distance, preferablyabout two inches.

It will be-seen thatthis arrangement-provides a cylindrical separating" unit, the periphery of which is openfor the admissionof fluid to the separator elements or baiiies-, the central portion of the unit.

within the conflnescfjtheinnermost bames {form-. ing a cylindrical ygas-fchamber I! closed'at its lower extremityand open at its upper extremity follsh the'reduced aperture l8.

, The various rows of fbaflies together form-a series of irregular passageways which. radiate tremities opening into the upper portion of the tank and theirlinner extremities opening intothe chamber I 9;

. In completing the assembly of this unit 9, a top to register with the opening it in the top spacer plate It. On the underside of the bottom spacer plate I! immediately back of each row of vertical baiiies I provide circular skirts or baiiles 22, 22,

24 and 25, respectively decreasing indiameter.

toward the axis of. the unit, said circular baiiies being welded to the underside of the spacer plate i1 and depending downwardly to a point preferably about two inches below the lower ends of the vertical baiiies III and Ilia.

,from'the axis ofthe unit with their outer .ex-

26 represents a circular liquid accumulator pan when this structure is completely assembled, the

circular bailles 22, 23, 2! and 25 extend a short 20 and top spacer plate It respectively, and opens into the gas chamber IS in the central portion of the separating unit 9. It will be noted that the chamber I9 is of a size suflicient to contain at all times and at a given pressure more gas than can be taken out of the gas outlet 5 at the same pressure, thus eliminating a pressure drop through the unit and permitting gas to be fed into the inner chamber I! in greater volume than it can be discharged therefrom at the same pressure by the gas line connected to the outlet 5.

The down-comer pipe 28 extends vertically downward to a predetermined point in the lower portion of the tank I, its lower end being preferably reduced as shown in dotted lines at 281: in Fig. 1. Just above the reduced end 28a 1 provide a flapper valve or vertical check valve II which is adapted to open downwardly to permit the flow of liquid extracted from the gas in the separating unit, down to the bottom of the separator tank, but at the same time to prevent the backing up of oil from. the tank into the downcomer pipe above the valve II.

There are times when a separator of this character is required to handle a large volume of gas and a relatively small amount of liquid in which event there is a possibility, due to the circular travel of the gas around the separator shell, that a considerable velocity would be developed in the movement of the gas. In other words, there is a likelihood of creating a vortex within the separator shell which would cause the liquid in the bottom of the separator to be mechanically picked up by the whirling gas. To overcome this disadvantage, I have provided a conical bailie 34 rigidly secured to the down-comer pipe 28 as shown in Figs. 1 and 3. This baille may be located at any point desired relative to the oil and gas inlets 2 but as shown in the drawings, its position is immediately below said inlets and its lower extremity is preferably spaced apart from the separator for a distance of approximately three inches providing an annular passageway 35' to permit the liquids to flow to the bottom of the tank. 36 represents a plurality of small apertures located near the apex of the baflle 34 in order to permit the upward escape of any gas which might be carried down with the liquid. Otherwise there would be a tendency for such gas to be bound on the underside of the baille.

32 represents an outlet pipe located in the bottom of the tank immediately adjacent the oil outlet 3 and provided on its underside with a small rectangular slot 33 extending longitudinally of the pipe. This slot is of such a length and width that it has a slightly greater capacity than the oil outlet 3, whereby the liquid level in the tank is more readily maintained at a constant point and the liquid is prevented from rushing toward the outlet opening to cause a disturbance in the liquid level.

Having thus described the construction and assembly of my improved oil and gas separator, its operation is as follows:-

A mixture of -oil and gas enters the through the inlets 2 and is directed at an angle to the inlet and spread out on the inner surface of the separatorshell in a thin circumferentially traveling film by means of the flow diverters 6, the liquids or solids following a downward spiral motion on the inside of the shell and the gas an upward spiral motion thereon. By spreading the oil and solids around'the inside of the separator, the entrained gas is given an Opp rtunity to become separated from the liquid and the difference in gravity between the two causes the gas to rise and the greater portion of the liquids tank or solids to drop. The liquids descend to the a bottom of the tank through the annular passageway 35 between the conical baflle 34 and the shell of the tank, and as before stated, if there is any tendency of the gas to create a vortex, the baille 34 prevents the liquids in the bottom of the tank from moving upwardly. v

The gasin its circular travel on the-inner wall of the separator, comes in contact with a wide surface and leaves the entrained liquids on the wall of the separator, proceeding upwardly and entering the separating unit 9 through the latters open periphery. This gas first comes in contact with the larger baiiles or veins in rows II and I2, then the small bafiles in row l3 and so on until it enters the gas outlet chamber IS in the central portion of the unit, from whence it is conducted upwardly through the gas outlet 5.

Although the basic principle of the operation of this separating unit 9 is fundamentally the same as that described in my former patent, the amount of surface contact for the gas is greatly increased for the size of the unit, compared with the box-type unit of my former patent.

The liquid knocked out of the gas in the separating unit travels down the inside of the vertical baflles l0 and Na and drops from the lower extremities thereof into the accumulator pan 26, where, due to the relative positions of the circular baflies 22, 23, 24 and 25 and the upper edge 29 of the down-comer pipe, a liquid sealis maintained and the gas is prevented from following the liquid down through the vertical bailles and coming up through a back row of baflles. When the liquid in the accumulator pan 26 reaches the level of the top edge 29 of the down-comer pipe, it enters the latter and is carried to the bottom of the separator and as the lower end of this down-comer pipe 28 is submerged in the liquid in the bottom of the tank,

a liquid seal is thus maintained at this point.

The check valve 3| in the down-comer pipe 28, as before stated, prevents the oil from backing up in the down-comer pipe which might otherwise be caused due to the lighter fractions of oil being taken out of the gas or due to the difl'erence in temperature of the oil at the bottom, which would ordinarily effect a bubbling or boiling of the oil in the bottom of the tank. Under' such conditions, the check valve l4 immediately closes and stops'any upward movement of the oil until such time as the pressure on the inside of the separator is equalized or the weight of the oil accumulated in the down-comer pipe on the other h side of the check valve is sufllcient to overcome any difference in pressure, whereupon the valve opensto permit the continued draining of oil from the unit 9.

The vertical bafiies or veins making up the separating unit l'are so' spaced as to give a maximum surface contact, and experiments in the ileldhaveshown that with this arrangement there is practically no pressure drop through the element and thus the. possibility of liquid being carried over with the gas is eliminated.

Obviously this separating unit can be constructed of any diameter desired with a greater or lesser number of'separating elements or bellies. In a five-foot separator I employ a thirty-inch separating unit with an eight-inch circular gas chamber in its center. This unit provides approximately two hundred and fifty-six (256) square feet of surface contact over which the gas passes, and the vertical bailies are so designed that the liquid once on the inside of the baiiie or vein is prevented from again coming in contact with the gas and is diverted downwardly into the accumulating pan 26. Now as proof of my statement that there is no pressure drop through the unit, it will be noted that in a thirty-inch unit such as just referred to, the smallest spaces between any of the vertical bafties are those between the small bailies of the last row l which in the unit under discussion collectively comprise an open area of 2.1 square feet, as against a six-inch outlet opening from the eight-inch gas chamber through the top. Hence all pressure drop over and above that necessary to cause gas flow and that due to friction, is eliminated.

As before stated, withthis design of separating unit, the possibility of oil being mechanically carried over with the gas is eliminated. The unit 9 is suspended in the center of the topportion of the tank and the gas with entrained liquids or solids having followed a circular path around the inside of the shell, 1 towards the top, the liquid contained therein gradually decreases as the gas nears the top of the separator. Thus due to the location of the unit in the center of the separator shell, the heaviest liquids and solids have left the gas before the latter enters the unit which permits said unit to act with greater efliciency against the light spray or mist which might be carried in the gas.

It will also be observed that by this arrangement, all gas must pass through the unit before reaching the gas outlet of the tank.

From the foregoing it is believed that the construction and advantages of my invention may be readily understood by those skilled in the art w;thout further description, it being borne in mind that numerous changes may be made in the details disclosed without departing from the spirit of the invention as set forth in the following claims.

What I- claim and desire to secure by Letters Patent is:--

1. Apparatus for separating liquid from gas including a tank forming a liquid settling chamher, an inlet opening in said tank, a liquid outlet for said settling chamber, a gas outlet in the upper portion of said tank, a separating unit arranged immediately anterior to said gas outlet, whereby any gases leaving said tank must first pass through said unit, said separating unit including a plurality of vertically disposed substantially trough-like baflies arranged in a series of co-axial circular rows with their mouths opening away from the axis of said unit, the bailles of each row being in staggered relation to the baifles of the adjacent rows and forming a-plurality of irregular passageways radiating from the axis of said unit and opening at their outer th upper the innerextremities.- ofs dminating in a cylindrical gaschamber centrally of said unit, the baiiles nearest said gas chamber being smaller in transverse dimension than the outer baflies, said gas chamber-being:

, in communication with said liquid receptacle, and

means adjacent said lower extremities for effecting a liquid seal in said receptacle to prevent; the passage of gas across said receptacle.

4. A separating unit for liquid and gas separators comprising a plurality of vertically disposed substantially trough-like baiiles arranged in a series of co-axial circular rows with their mouths opening away from the axis of said unit, the baiiies of each row being in staggered relation to the baflles of the adjacent rows and forming a series of irregular passageways radiating from the axis of said unit, the outer extremities of said passageways opening at the periphery of the unit and their inner extremities opening into a central cylindrical gas chamber, the battles nearest the gas chamber being smaller in transverse dimension than the outer bailles, an outlet for said gas chamber at the top of said unit, a liquid receptacle in the lower portion of said unit, and means for conducting liquids therefrom.

5. A separating unit as claimed in claim 4 including means for closing the upper ends of said bafiles, their lower ends opening in communication with said liquid receptacle, and a liquid seal adjacent said lower ends to prevent the passage of gas across said receptacle.

6. A separating unit as claimed in claim 4 including spaced plates adjacent the vertical extremities of said baffles for retaining the latter in the proper spaced relation, means for closing the upper ends of said baffles, the lower ends of the same extending through the adjacent spacer plate predetermined distance and opening into said-liquid receptacle, circular baflles secured to the undersurface of said last named spacer plate and depending into said receptacle 9. predetermined distance beyond the lower extremities of the respective baflies to form a liquid seal, and means for maintaining a predetermined liquid level in said receptacle.

'7. Apparatus for separating liquid from gas including a tank forming a liquid settling chamber, an inlet opening in said tank, means adjacent said inlet opening for diverting the flow of the mixture entering the tank to cause the same to travel circumferentially of the wall of said tank, a liquid outlet for said settling chamber, a gas outlet in the upper portion of said tank, a separating unit arranged immediately anterior to said gas outlet, whereby any gases leavingsaid tank must first pass through said unit, said separating unit including a plurality of vertically disposed substantially trough-like baflles arranged in a series of co-axial circular rows, with their mouths opening away from the axis of said unit, the battles of each row being in staggered relation to the baffles-of the adjacent rows and forming a plurality of irregular passageways radiating from the axis of said unit and. opening at their outer extremities into the upper portion of said tank, the inner extremities of said passageways terminating in a cylindrical gas chamber disposed centrally of said unit, the bafiles nearest said gas chamber being smaller in transverse dimension than the outer bafiies, said gas chamber being in communication with the gas outlet of said tank, a liquid receptacle in said unit, a drain pipe leading from said receptacle to said settling chamber, and a check valve in said drain pipe to prevent the oil in said settling chamber from backing up in the drain pipe.

8. Apparatus as claimed in claim 7 wherein said means for diverting the flow of incoming fluid comprises a flat substantially fan-shaped bafile plate secured to the wall of said tank and. spaced inwardly from said inlet, the upper and lower edges of said plate being bent toward the shell of the tank to form flanges, and an elongated transversely restricted opening formed between said plate and the shell of said tank, said opening having substantially the exact capacity of said inlet, whereby the fluid entering saidinlet is directed circumferentially of the wall of said tank and spread out in a thin film.

9. Apparatus as claimed in claim '7 wherein the lower portion of said settling chamber is provided with a transversely extending pipe opening into the settling chamber at one end with its other end in communication with the liquid outlet, said pipe having a longitudinally extending restricted slot in the wall thereof whereby a disturbance of the liquid level is prevented.

10. Apparatus as claimed in claim '7 wherein the lower portion of said settling chamber is provided with a transversely extending pipe opening into the settling chamber at one end with its other end in communication with the liquid outlet, said pipe having a longitudinally extending restricted slot in the wall thereof, said slot being of slightly greater capacity than that of said liquid outlet, whereby a disturbance of the liquid level is prevented.

11. A separating unit for liquid and gas separators comprising a plurality of vertically disposed substantially trough-like baifles arranged in a series of co-axial circular rows with their mouths opening away from the axis of said unit,

the baiiles of the respective rows gradually decreasing in transverse dimensions toward the axis of said unit and being arranged in staggered relation to the baflles of the adjacent rows to form a series of irregular passageways radiating from the axis of said unit, the outer extremities of said passageways opening at the periphery of the unit and their inner extremities opening into a central cylindrical gas chamber, an outlet for said gas chamber at the top of said unit, a liquid receptacle in the lower portion of said unit, and means for conducting liquids therefrom.

12. A separating unit as claimed in claim 11 wherein the baffles of at least some of said rows are provided with vertically extending inturned flanges adjacent their mouths.

13. A separating unit as claimed inv claim 11 wherein the baflies of some of said rows are provided with vertically extending inturned flanges adjacent their mouths, and the bafiies of other rows consist of members which are angular in cross section.

14. A separating unit for liquid and gas separators comprising a plurality of vertically disposed substantially trough-like baflies arranged in a series of co-axial circular rows with their mouths opening away from the axis of said unit, the baffles of the respective rows gradually decreasing in transverse dimensions toward the axis of said unit and being arranged in staggered relation to the baffles of the adjacent rows to form a series of irregular passageways radiating from the axis of said unit, the outer extremities of said passageways opening at the periphery of the unit and their inner extremities opening into a central cylindrical gas chamber, a restricted outlet for said gas chamber at the top of said unit, a liquid receptacle in the, lower portion of said unit, means for conducting liquids from the latter, the lower ends of said baffles being in communication with said liquid receptacle, means for maintaining a predetermined liquid level in said receptacle, and a series of circular baiiles arranged adjacent the lower extremities of the bafiles of each row and depending into the liquid in said receptacle to preventthe passage of gas across said receptacle from one row of baiiles to another.

MILLARD F. WATERS.

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